U.S. patent application number 10/971304 was filed with the patent office on 2006-04-27 for print media and methods for making the same.
Invention is credited to Bor-Jiunn Niu, Stefan Schuttel.
Application Number | 20060088673 10/971304 |
Document ID | / |
Family ID | 35447565 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060088673 |
Kind Code |
A1 |
Niu; Bor-Jiunn ; et
al. |
April 27, 2006 |
Print media and methods for making the same
Abstract
Print media which includes at least one ink-receiving layer
comprising at least one anionic fluorosurfactant and may be
positioned over the substrate and/or be supported by the
substrate.
Inventors: |
Niu; Bor-Jiunn; (San Diego,
CA) ; Schuttel; Stefan; (Murten, CH) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD
INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
35447565 |
Appl. No.: |
10/971304 |
Filed: |
October 21, 2004 |
Current U.S.
Class: |
428/32.34 |
Current CPC
Class: |
B41M 5/529 20130101 |
Class at
Publication: |
428/032.34 |
International
Class: |
B41M 5/40 20060101
B41M005/40 |
Claims
1. A print media, comprising a substrate; and at least one
ink-receiving layer positioned over the substrate, the
ink-receiving layer comprising at least one anionic
fluorosurfactant.
2. The print media of claim 1, wherein the at least one
ink-receiving layer is comprised of from about 0.1 to about 1 part
anionic fluorosurfactant.
3. The print media of claim 1, wherein the at least one
ink-receiving layer further comprises at least one binder.
4. The print media of claim 1, further comprising at least one
additional material layer positioned between the substrate and the
at least one ink-receiving layer.
5. The print media of claim 4, wherein the at least one additional
material layer comprises at least one binder.
6. The print media of claim 1, wherein the at least one
ink-receiving layer is directly affixed to the substrate.
7. The print media of claim 6, wherein the at least one additional
material layer comprises at least one binder.
8. The print media of claim 1, wherein the substrate further
comprises a first side and a second side, and wherein at least one
of the first side and the second side comprises a coating layer
thereon comprised of polyethylene.
9. A print media, comprising: a substrate; and at least one
ink-receiving layer supported by the substrate, the ink-receiving
layer comprising at least one anionic fluorosurfactant.
10. The print media of claim 9, wherein the at least one
ink-receiving layer is comprised of between about 0.1 to about 1
part anionic fluorosurfactant.
11. The print media of claim 9, wherein the at least one
ink-receiving layer further comprises at least one binder.
12. The print media of claim 9, further comprising at least one
additional material layer positioned between the substrate and the
at least one ink-receiving layer.
13. The print media of claim 9, further comprising at least one
additional material layer positioned over and above the at least
one ink-receiving layer.
14. A coating formulation for use in preparing an ink-receiving
layer, the coating formulation comprising at least one anionic
fluorosurfactant.
15. The coating formulation of claim 14, wherein the coating
formulation is comprised of from about 0.1 to about 1 part anionic
fluorosurfactant.
16. The coating formulation of claim 14, wherein the coating
formulation further comprises at least one binder.
17. A method for producing a print media, comprising: providing a
substrate; and forming at least one ink-receiving layer in position
over the substrate, the ink-receiving layer comprising at least one
anionic fluorosurfactant.
18. The method of claim 17, wherein forming at least one
ink-receiving layer comprises forming the ink-receiving layer
comprising from about 0.1 to about 1.0 part anionic
fluorosurfactant.
19. The method of claim 17, further comprising forming at least one
additional material layer positioned between the substrate and the
at least one ink-receiving layer.
20. The method of claim 17, further comprising forming at least one
additional material layer in position over and above the at least
one ink-receiving layer.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to media for receiving printed
images thereon. More specifically, the present invention relates to
media including a substrate and at least one ink-receiving layer
over the substrate, the ink-receiving layer comprising at least one
anionic fluorosurfactant.
BACKGROUND OF THE INVENTION
[0002] In order to effectively generate printed images using
various ink transfer techniques and systems known to those of
ordinary skill in the art (e.g., thermal inkjet technology),
ink-receiving print media having particular characteristics must be
employed. Ideally, to achieve maximum efficiency, print media
should be able to provide a number of benefits and advantages
including, without limitation, a high level of light-fastness, a
high level of smear-fastness, and the ability to quickly and
completely absorb ink materials in a manner which minimizes or
avoids image distortion. As used herein, the terms "light-fast",
"light-fastness", and the like refer to the capacity of a print
media to retain images thereon in a stable manner without
substantial fading, blurring, distortion, and the like over time in
the presence of natural or man-made light. The terms "smear-fast",
"smear-fastness", and the like, as used herein, refer to the
production of images that exhibit minimal to no smearing or
blurring when rubbed or otherwise physically engaged with a variety
of objects.
[0003] Of particular concern are so-called "pick-up tire" markings
and pressure markings. "Pick-up tire markings" may occur when, for
example, a surface contaminant is transferred from a component of
the printing apparatus (e.g., a roller used to pick up the print
media and transport in through the printer) to the print media.
Pressure markings (sometimes referred to as "fingerprinting") may
occur due to pressure applied to the printed image by the print
operator's hands, fingers, and the like. Pick-up tire markings and
pressure markings may generate printed images wherein the dot size
in the contaminated or marked regions of the print media is
overspread or increased relative to the dot size in the
uncontaminated or unmarked regions. This causes the printed images
to appear smeared or blurred.
[0004] It is known in the art to apply coating formulations to one
or more ink-receiving surfaces of a print media in an attempt to
achieve a number of desirable results. However, such coating
formulations often cause images to be generated which are not
substantially light-fast and/or substantially smear-fast. That is,
the images produced on the coated print media may still exhibit
pick-up tire markings and/or pressure markings and may appear
faded, blurred, and/or distorted over time.
BRIEF SUMMARY OF THE INVENTION
[0005] The present invention provides a print media including a
substrate and at least one ink-receiving layer. The ink-receiving
layer comprises at least one anionic fluorosurfactant and may be
positioned over or above the substrate.
[0006] The present invention further provides a coating formulation
for use in preparing an ink-receiving layer, the coating
formulation comprising at least one anionic fluorosurfactant.
[0007] Additionally, the present invention provides a method for
producing a print media comprising providing a substrate and
forming at least one ink-receiving layer over and above the
substrate, the ink-receiving layer comprising at least one anionic
fluorosurfactant.
[0008] Other features and advantages of the present invention will
become apparent to those of ordinary skill in the art through
consideration of the ensuing description, the accompanying
drawings, and the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] While the specification concludes with claims particularly
pointing out and distinctly claiming that which is regarded as the
present invention, the advantages of this invention may be more
readily ascertained from the following description of the invention
when read in conjunction with the accompanying drawings in
which:
[0010] FIGS. 1A and 1B schematically illustrate a partial
cross-sectional, sequential view of the process steps that may be
employed to produce a print media in accordance with one embodiment
of the present invention;
[0011] FIGS. 2A-2C schematically illustrate a partial
cross-sectional, sequential view of the process steps that may be
employed to produce a print media in accordance with another
embodiment of the present invention wherein the completed print
media includes an additional material layer positioned over an
ink-receiving layer; and
[0012] FIGS. 3A-3C schematically illustrate a partial
cross-sectional, sequential view of the process steps that may be
employed to produce a print media in accordance with yet another
embodiment of the present invention wherein the completed print
media includes an additional material layer positioned between a
coating layer formed over the substrate and an ink-receiving
layer.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The present invention is directed to media for receiving
substantially smear-fast and substantially light-fast printed
images thereon. More specifically, the present invention is
directed to print media having a substrate and at least one
ink-receiving layer over the substrate, the ink-receiving layer
comprising at least one anionic fluorosurfactant. The particular
embodiments described herein are intended in all respects to be
illustrative rather than restrictive. Other and further embodiments
will become apparent to those of ordinary skill in the art to which
the present invention pertains without departing from its
scope.
[0014] The print media disclosed herein shall not be restricted to
any particular component types, sizes, material-selections,
arrangements of print media material/structures, chemical
compositions, layering sequences, numbers of layers, layer
orientations, thickness values, porosity parameters, material
quantities, and other related factors unless otherwise expressly
stated herein. For instance, it shall be understood and appreciated
by those of ordinary skill in the art that one or more
ink-receiving layers, each layer comprising at least one anionic
fluorosurfactant, may be employed in connection with the print
media of the present invention. In this regard, the print media
disclosed herein shall not be restricted to any number of
ink-receiving layers provided that at least one ink-receiving layer
is utilized. Likewise, the location of the ink-receiving layer(s)
of interest on or within the print media(s) may be varied as
desired and employed in combination with one or more other material
layers located above or below the claimed layer(s) of concern. It
should therefore be emphasized that the print media under
consideration shall cover the ink-receiving layer (or layers) of
interest (namely, those that comprise at least one anionic
fluorosurfactant) regardless of where such layer(s) are located,
provided that they are able to receive on or within at least a
portion of the ink compositions being delivered by the chosen
printing system. Accordingly, the claimed subject matter shall be
construed in its broadest sense to cover a print media (and method
for producing the same) which employs at least one ink-receiving
layer having at least one anionic fluorosurfactant therein so that
this layer may receive at least a portion of the ink materials
being delivered.
[0015] The print media and methods disclosed herein may be
applicable to a wide variety of printing systems with particular
reference to those that employ thermal inkjet technology. Likewise,
a number of different ink materials may be used in connection with
the print media discussed herein without limitation. As used
herein, the term "ink materials" refers to compositions
incorporating dyes, pigments, liquid or solid toners, powders,
waxes, dispersions, and other colorants without restriction.
Furthermore, such materials (e.g., colorants) shall encompass both
chromatic (e.g., colored) and achromatic (e.g., black/white) ink
materials. In this regard, the claimed print media shall not be
considered "ink-specific" or "printing method-specific" in any
fashion.
[0016] It will also be understood and appreciated by those of
ordinary skill in the art that the present invention shall not be
limited to any particular construction techniques (including any
given material deposition procedures, layering arrangements,
fabrication processes, and the like) unless otherwise indicated.
For instance, the terms "forming", "applying", "positioning",
"operatively attaching", "providing", and grammatical variants
thereof as used throughout this disclosure and as claimed shall
broadly encompass any appropriate manufacturing procedures
including, without limitation, roll-coating, spray-coating;
immersion-coating, cast-coating, slot-die coating, curtain coating,
rod-coating, blade-coating, roller application, manual or automatic
dipping, brush-coating, and other related production methods. In
this regard, the invention shall not be considered "production
method-specific" unless otherwise expressly stated herein, with the
recitation of any particular fabrication techniques, layer
deposition methods, number of layers applied in a given step, layer
orientations, layer thicknesses, and the like being set forth for
exemplary purposes only.
[0017] Likewise, it shall be understood that the terms "operative
attachment", "in operative attachment", "operatively attached",
"operatively positioned", "positioned on", "positioned above",
"positioned over and above", "formed over and above", "formed
under", "supported by", and the like as used herein shall be
broadly construed to encompass a variety of divergent layering
arrangements and assembly techniques. These arrangements and
techniques include, by way of example only, the direct attachment
of one material layer to another material layer with no intervening
material layers therebetween, and the attachment of one material
layer to another material layer with one or more material layers
therebetween provided that the one layer being "supported by",
"attached to", or "positioned over and above" the other layer is
somehow "supported by" the other layer (not withstanding the
presence of one or more additional material layers therebetween).
Use of the phrase "direct attachment", "directly attached on",
"directly attached to", "directly positioned on", "directly located
on", "directly affixed to", and the like shall signify a situation
wherein a given material layer is secured to another material layer
without any intervening material layers therebetween.
[0018] Any statement used herein which indicates that one layer of
material is "above", "over", "positioned over and above", or "on
top of" another layer shall involve a situation wherein the
particular layer that is "above", "over", "over and above", or "on
top of" the other layer in question shall be the outermost of the
two layers relative to the external environment. The opposite
situation will be applicable regarding use of the terms "below",
"under", "beneath", "on the bottom of", and the like. The
characterizations recited above (with particular reference to "over
and above") shall be effective regardless of orientation of the
print media under consideration and, for example, shall encompass a
situation where the ink-receiving layer of interest may be placed
on either side of the substrate in question. Again, in the current
invention, the claimed ink-receiving layer or layers may be located
at any position on or within the print media provided that at least
some of the ink materials being delivered by the chosen printing
system are able to come in contact with such layer or layers,
followed by the receipt of ink materials therein and/or thereon.
Thus, while some or all of the drawing figures associated with this
invention (and the embodiments discussed below) shall illustrate
the claimed ink-receiving layer(s) on top of the substrate as the
uppermost/outer-most structures which are exposed to the external
environment with no other layers thereon, the claimed invention
shall not be restricted to this design. In this regard, one or more
other layers of material may be placed over or under the
ink-receiving layers of interest in accordance with the explanation
provided above.
[0019] Additionally, the terms "top", "uppermost", and "outermost"
as applied to a given layer in the claimed structure shall again be
construed to involve that layer which is at the top of the print
media in question with no other layers thereon that are exposed to
the external environment. When such layer faces the ink delivery
components of the printer unit, it is typically the first component
of the media to receive incoming ink materials with no other layers
thereon. Likewise, any indication herein regarding a given layer
being located "over and above" (or some other equivalent phrase)
the substrate under consideration shall include a situation where
the layer of concern is positioned over (e.g., on top of) the
substrate either directly with no intervening layers being present
or with one or more intervening layers therebetween. That is, the
foregoing phrase (e.g., "over and above" and equivalents thereto)
as it applies to a given layer shall be construed to include a
situation where such layer is somehow above the substrate (e.g.,
outermost as previously defined relative to the substrate) whether
or not any intervening layers are located between the substrate and
the layer of concern.
[0020] Furthermore, any indication that the ink-receiving layer(s)
(or other layers set forth herein) are somehow "supported by" the
substrate under consideration (whether coated or uncoated as
discussed hereinbelow) shall signify a situation where the layer(s)
in question reside on the substrate and are directly attached
thereto as previously defined or indirectly attached thereto with
one or more layers therebetween. In such a situation, the layer(s)
of concern rely on the substrate for structural support whether or
not there are any intervening layers therebetween.
[0021] While the print media disclosed herein will be discussed
with primary reference to thermal inkjet technology, it shall be
understood that they may be employed in connection with different
ink delivery systems and methods including, but not limited to,
piezoelectric drop devices of the variety disclosed in U.S. Pat.
No. 4,329,698 and dot matrix units of the type described in U.S.
Pat. No. 4,749,291, as well as comparable and diverse systems
designed to deliver ink using one or more ink delivery
components/assemblies. In this regard, the claimed print media and
methods shall not be considered "print method-specific". U.S. Pat.
Nos. 4,329,698 and 4,749,291 are both incorporated herein by
reference in their entireties.
[0022] Exemplary printer units which are suitable for use with the
print media of the present invention include, by way of example
only, DESKJET.RTM. printers (e.g., DESKJET.RTM.400C, 500C, 540C,
660C, 693C, 820C, 850C, 870C, 895CSE, 970CSE, 990CXI, 1200C, and
1600C), DESIGNJET.RTM. printers (e.g., DESIGNJET.RTM. 5000 series),
and PHOTOSMART.RTM. printers(e.g., PHOTOSMART.RTM. P100 and P130),
each of which is manufactured and sold by the Hewlett-Packard
Company of Palo Alto, Calif. (USA).
[0023] Furthermore, the claimed invention (namely, the novel print
media and production methods associated therewith) are not
"ink-specific" and may be used in connection with a variety of
inks, dyes, pigments, liquid and solid toner compositions,
sublimation dyes, colorants, stains, waxes, and the like without
restriction. For instance, representative ink compositions that can
be employed in connection with the print media materials of the
invention include, but are not limited to, those discussed in U.S.
Pat. Nos. 4,963,189 and 5,185,034 (both incorporated herein by
reference in their entireties) which represent only a small
fraction of the ink compositions and colorant formulations that can
be used with the claimed print media.
[0024] Referring now to the drawings in general, and initially to
FIG. 1B in particular, a completed print media (also referred to
herein as a "print media sheet", "ink-receiving sheet",
"ink-receiving substrate", "ink-receiving member", and the like) in
accordance with one embodiment of the present invention is
illustrated and designated generally as reference numeral 10. Print
media 10 includes a substrate 12 and an ink-receiving layer 14. The
substrate 12 may be fabricated in the form of a flexible sheet
comprising an upper surface 16 (also characterized herein as a "top
surface") and a lower surface 18 (also characterized herein as a
"bottom surface"), with both surfaces 16, 18 being substantially
planar and having a uniform surface texture in the representative
embodiment of FIG. 1B. Alternatively, the substrate 12 may be
configured in roll, web, strip, film, or sheet form with
transparent, semi-transparent, or opaque characteristics as
desired. The other layers and materials associated with the print
media 10 reside on this structure and are supported thereby.
[0025] In one embodiment of the print media 10, the substrate 12
may have an exemplary and non-limiting uniform thickness "T" along
its entire length of between about 0.025 and about 0.38 mm (between
about 1 and about 15 mils). It is currently preferred that the
substrate 12 have a thickness of between about 0.15 and about 0.25
mm (between about 6 and 10 mils). Substrate 12 may comprise,
without limitation, cellulosic (e.g., cellulose-containing) paper,
photopaper, paperboard, wood, cloth, non-woven fabric, felt,
synthetic (e.g., non-cellulosic) paper, ceramic compositions
(optimally unglazed), glass or glass-containing products, vinyl,
metals (e.g., in foil form made from, for instance, aluminum (Al),
silver (Ag), tin (Sn), copper (Cu), mixtures thereof), as well as
composites and/or mixtures of such materials. Likewise, various
organic polymer compositions may be employed to form the substrate
12 including, without limitation, those fabricated from
polyethylene, polystyrene, polyethylene terephthalate,
polycarbonate resins, Teflon.RTM. (polytetrafluoroethylene),
polyimide, polypropylene, cellulose acetate, poly(vinyl chloride),
and mixtures thereof.
[0026] While the present invention shall not be restricted to any
particular substrate 12, commercially-available photobase paper, in
sheet form, is a currently preferred. An exemplary photobase paper
which may be used in the print media 10 of the present invention is
HP Premium Photopaper (Glossy) sold by the Hewlett-Packard Company
of Palo Alto, Calif. (USA).
[0027] The ink-receiving layer 14 may be positioned over and above
and/or be supported by the substrate 12 and comprises at least one
anionic fluorosurfactant. The primary functions of the anionic
fluorosurfactant are to adjust the surface energy of the print
media 10 and to facilitate coatability during the manufacturing
process. Furthermore, the range of surface energy provided from the
anionic fluorosurfactant minimizes or prevents overspread of the
ink dot size and, accordingly, minimizes pick-up tire markings and
pressure markings. An exemplary anionic fluorosurfactant which may
be used in the ink-receiving layer 14 of the present invention is
Zonyl.RTM. FSA available from DuPont of Wilmington, Del. (USA).
Zonyl.RTM. FSA has the structure:
RfCH.sub.2CH.sub.2SCH.sub.2CH.sub.2CO.sub.2Li
[0028] wherein Rf is F(CF.sub.2CF.sub.2).sub.x, and wherein x is
between about 1 and about 9.
[0029] The ink-receiving layer 14 may also comprise one or more
organic or inorganic binder compositions (also characterized as
simply "binders"). The term "binder" as used herein refers
generally to compositions which have the ability to chemically,
physically, electrostatically, or otherwise retain one or more
materials together in a given formulation or structure in order to
provide mechanical strength, cohesiveness, and the like.
[0030] A first exemplary binder that may be used in conjunction
with the at least one anionic fluorosurfactant in the ink-receiving
layer 14 of the present invention is gelatin. Gelatin basically
consists of a product which is derived from hydrolysis of animal
connective tissues. Gelatin is particularly useful for the
production of ink-receiving layers employed in print media of the
type disclosed herein as it is characterized by a high fluid
absorption capacity which is especially desirable when ink
materials are being delivered to a chosen print media. A high
absorption capacity in a print media may permit rapid drying times,
the ability to retain substantial amounts of ink in order to
efficiently generate large-scale multi-color images, the avoidance
of color bleed (namely, the undesired blending of multi-colored
inks into each other during the printing process), as well as a
high level of stability when the image is exposed to light and
moisture. Additional benefits provided by the use of gelatin in the
ink-receiving layer 14 may include, but are not limited to,
improved image permanence, better humid-fastness, and good
light-fastness. While the claimed invention shall not be restricted
to any particular types, grades, or varieties of gelatin, a
representative photographic grade gelatin material that is
appropriate for use in the ink-receiving layer 14 (and any
additional layers if desired, as more fully described below) is
commercially available from DGF Stoess AG of Eberbach, Germany.
This particular gelatin tends to promote an improved interaction
between the ink-receiving layer 14 and the colorants being
delivered thereto as well as provides favorable viscosity and bloom
levels.
[0031] A second exemplary binder composition that may be used in
conjunction with the at least one anionic fluorosurfactant in the
ink-receiving layer 14 of the present invention is polyvinyl
alcohol (PVOH). The basic structural formula for PVOH is as
follows: (--CH.sub.2CHOH--).sub.x
[0032] wherein x is between about 1 and about 10000. Polyvinyl
alcohol is commercially available from numerous sources including,
but not limited to, Nippon Gohsei of Osaka, Japan under the product
designation GOHSENOL NH-26, as well as Air Products and Chemicals,
Inc. of Allentown, Pa. (USA) under the product designation
Airvol.RTM. 523.
[0033] Exemplary and non-limiting derivatives of PVOH which shall
be encompassed within the term "polyvinyl alcohol" as used herein
include but are not limited to unsubstituted PVOH (as illustrated
and discussed above), carboxylated PVOH, sulfonated PVOH,
acetoacetylated PVOH, and mixtures thereof. Acetoacetylated PVOH
has the following basic structural formula:
(--CH.sub.2CHOH--).sub.x(--CH.sub.2CHOCOCH.sub.2COCH.sub.3--).s-
ub.y
[0034] wherein x is between about 1 and about 10000 and y is
between about 1 and about 100. Acetoacetylated PVOH is commercially
available from numerous sources including, for example, Nippon
Gohsei of Osaka, Japan, under the product designation GOHSEFIMER Z
200. With respect to the use of PVOH as a binder composition, in a
preferred embodiment, "straight" (e.g., unsubstituted) PVOH binders
can be used.
[0035] The term "polyvinyl alcohol" as used herein shall encompass
polyvinyl alcohols which are "fully hydrolyzed" or "partially
hydrolyzed". During the production process associated with PVOH,
varying degrees of hydrolysis can occur whereby, in certain
situations, residual acetate groups (--OCOCH.sub.3) are left within
the PVOH backbone (depending on a wide variety of production and
reaction parameters). For example, a PVOH molecule is traditionally
considered to be "fully hydrolyzed" if less than about 1.5 mole
percent acetate groups are left on the molecule.
[0036] In addition, the term "polyvinyl alcohol" shall also be
defined and interpreted herein to encompass structures wherein the
PVOH component thereof is considered to be "partially hydrolyzed".
Partially hydrolyzed PVOH is typically defined to include PVOH
molecules wherein about 1.5 to as much as about 20 mole percent or
more acetate groups are left on the molecule. Again, the extent of
hydrolysis will depend on a wide variety of production parameters.
Polyvinyl alcohols having a hydrolysis level of between about 88%
and about 99% are currently preferred. An exemplary 88% hydrolyzed
PVOH is available from Clariant Corporation of Charlotte, N.C.
(USA) under the product designation PVOH 2688.
[0037] Copolymers of PVOH may also be used as binder compositions
in conjunction with the at least one anionic fluorosurfactant in
the ink-receiving layer 14 of the present invention. The term
"copolymer" as used herein shall be construed in a traditional
fashion to encompass a polymer composition which is the product of
two or more different compounds or groups which are used to form
the polymeric structure/backbone. An exemplary PVOH copolymer that
may be used in the ink-receiving layer 14 of the present invention
is a modified PVOH available from Nippon Gohsei of Osaka, Japan,
under the product designation PVOH-WO-320. PVOH-WO-320 is a
copolymer of polyvinyl alcohol and polyethylene oxide. Another
exemplary PVOH copolymer that may be used in the ink-receiving
layer 14 of the present invention is a proprietary polymer of
styrene-acrylate copolymer containing secondary amines available
from PPG Industries, Inc. of Pittsburgh, Pa. (USA). This
proprietary polymer is considered a cationic copolymer and, when
used, may also function as a dye fixer (cationic mordant) to
minimize dye diffusion.
[0038] Use of PVOH as a binder can offer a number of benefits in
the ink-receiving layer 14 including, but not limited to, a high
degree of binding strength, color accuracy, and bleed control, as
well as improved color gamut.
[0039] Representative and non-limiting examples of additional
binders which may be employed of the ink-receiving layer 14 (and/or
in other layers in the print media 10, as more fully described
below) include, without limitation, starch, SBR latex, alginates,
carboxycellulose materials (for example, methyl-hydroxypropyl
cellulose, ethylhydroxypropyl cellulose, and the like), polyacrylic
acid and derivatives thereof, polyvinyl pyrrolidone, casein,
polyethylene glycol, polyurethanes (for example, a modified
polyurethane resin dispersion), polyamide resins (for instance, an
epichlorohydrin-containing polyamide), poly(vinyl acetate-ethylene)
copolymer, poly(vinyl pyrrolidone-vinyl acetate) copolymer, and
mixtures thereof.
[0040] Representative polyurethanes that are suitable for use as
additional binder compositions alone or combined with the other
binder compositions disclosed herein include, without limitation,
the sub-class of compounds including water-soluble or
water-dispersible polyurethane polymers, water-soluble or
water-dispersible modified polyurethane resin dispersions, and
mixtures thereof. Of particular interest is the employment of at
least one modified polyurethane resin dispersion. The term
"modified polyurethane resin dispersion" shall be generally defined
herein to encompass polyurethane polymers having hydrophobic groups
associated therewith, wherein such materials are water-dispersible.
While many different modified polyurethane resin dispersions are
commercially available from numerous sources (and are typically
proprietary in nature), an exemplary modified polyurethane resin
dispersion that may be used as an additional binder composition in
conjunction with the at least one anionic fluorosurfactant in the
ink-receiving layer 14 of the present invention is a product sold
by Dainippon Ink and Chemicals/Dainippon International (USA), Inc.
of Fort Lee, N.J. (USA) under the product designation PATELACOL
IJ-30. Further, general information concerning this type of
material (with particular reference to polyurethane
dispersions/emulsions) is provided in Japanese Patent Publication
No. 10-181189 which is incorporated herein by reference in its
entirety. However, other polyurethane-based materials shall also be
appropriate for use as additional binders within the ink-receiving
layer 14 (or other layers, as more fully described below), with the
above-listed composition being provided for example purposes
only.
[0041] Regarding the employment of polyamide resins as additional
binder compositions in conjunction with the at least one anionic
fluorosurfactant in the ink-receiving layer 14 of the present
invention, the following chemicals may be encompassed within this
class of compounds without limitation: acrylic modified polyamides,
acrylic polyamide copolymers, methacrylic modified polyamides,
cationic polyamides, polyquaternary ammonium polyamides,
poly(styrene-acrylic) copolymers, epichlorohydrin-containing
polyamides, and mixtures thereof. One composition of particular
interest within this group is an epichlorohydrin-containing
polyamide. The term "epichlorohydrin-containing polyamide" shall be
generally defined to involve an epichlorohydrin group-containing
polyamide formulation, with this composition having the following
basic structural/chemical formula:
(C.sub.6H.sub.10O.sub.4.C.sub.4H.sub.13N.sub.3.C.sub.3H.sub.5ClO).sub.x
[0042] wherein x is between about 1 and about 1000.
Epichlorohydrin-containing polyamides are commercially available
from, for example, Georgia Pacific Resins, Inc. of Crosett, Ark.
(USA) under the product designation AMRES 8855.
[0043] In an exemplary and non-limiting embodiment, the
ink-receiving layer 14 may contain between about 0.1 and about 1
part anionic fluorosurfactant and between about 99.9 and about 99
parts binder.
[0044] The ink-receiving layer 14 may further comprise one or more
additional components without limitation. One such additional
component may be at least one pigment composition. The terms
"pigment" or "pigment composition" as used herein mean a material
which is used to impart color, opacity, and/or structural support
(e.g., in a "filler" capacity) to a given formulation. The
ink-receiving layer 14 shall not be restricted to any given pigment
compositions (organic or inorganic in nature), pigment quantities,
or number of pigments in combination. For example, boehmite,
pseudo-boehmite, or a mixture thereof can be used as an exemplary
pigment composition in the ink-receiving layer 14. The terms
"boehmite" and "pseudo-boehmite" shall be defined in a conventional
fashion as would normally be understood and appreciated by those of
ordinary skill in the art. For example, boehmite traditionally
involves a crystalline compound having the empirical formula
AlO(OH) (including all physical forms in which boehmite exists or
may otherwise be produced). In addition, "pseudo-boehmite" (also
known as "gelatinous boehmite") traditionally encompasses a type of
boehmite having a higher water content than "regular" crystalline
boehmite of the variety mentioned above.
[0045] The term "slip agent" as used herein refers to an agent that
aids in reducing the friction levels of the completed ink-receiving
layer 14 in order to make it smoother and more readily transferable
through the printer unit(s) of interest. Exemplary slip agents
include, by way of example only, products available from Elementis
Specialties of Heightstown, N.J. (USA) under the product
designation Slip-Ayd.RTM. (e.g., SL 1618) and
polytetrafluoroethylene beads which are commercially available
from, for instance, Shamrock Technologies, Inc. of Newark, N.J.
(USA) under the product designation Fluoro AQ-50.
[0046] The term "pH modifier" as used herein refers to an agent
which aids in achieving a desired pH level during formulation of
the ink-receiving layer 14 (with a currently preferred pH level
being between about three and about six). Exemplary pH modifiers
include, without limitation, hydrochloric acid, sulfuric acid,
citric acid, and mixtures thereof.
[0047] The term "gelatin hardener" as used herein refers to a
composition which aids in hardening and otherwise assists in the
overall solidification of any gelatin materials used in the
formulation of the ink-receiving layer 14. Exemplary gelatin
hardener compositions include, by way of example only,
pyridinium-carbamoyl, metal oxides, aldehydes, amides, and vinyl
sulfone.
[0048] The term "ink-fixative" as used herein refers to an agent
which chemically, physically, or electrostatically binds with or
otherwise fixes the ink materials of interest to, within, or on the
ink-receiving layer 14. Exemplary ink fixatives include, without
limitation, quarternary amine emulsion polymers, an example of
which includes a proprietary composition that is commercially
available from the Rohm and Haas Company of Philadelphia, Pa. (USA)
under the product designation Primal.RTM. PR-26.
[0049] Various other additional ingredients may be incorporated
within the ink-receiving layer 14 in addition to or instead of
those recited above without limitation including biocides (for
example, chlormetakresol), UV/light protectants and/or absorbents,
fade-control agents, fillers, preservatives (e.g., antioxidants),
buffers, wetting agents, plasticizers (humectants) and the
like.
[0050] In an exemplary and non-limiting embodiment, the
ink-receiving layer 14 may have a uniform thickness "T.sub.2" (FIG.
1B) along its entire length of between about 1 .mu.m and about 50
.mu.m (preferably between about 15 .mu.m and about 25 .mu.m.
[0051] If desired, substrate 12 may be coated on at least one of
the upper and lower surfaces 16, 18 thereof with a selected coating
material or formulation that is substantially non-porous,
non-absorbent, and ink-permeable. In the representative embodiment
illustrated in FIG. 1B, a coating layer 20 is provided on the upper
and lower surfaces 16, 18 of the substrate 12. The coating layer 20
may have a uniform thickness "T1" of between about 1 .mu.m and
about 40 .mu.m. It is currently preferred that the coating layer 20
have a uniform thickness T1 between about 10 .mu.m and about 30
.mu.m. The coating layer 20 may be produced from a number of
compositions without limitation, with such compositions (and the
use of a coating layer 20 in general) being selected in accordance
with numerous factors including the type of ink being delivered,
the printing system in which the print media 10 will be used, and
the like. If a non-porous, non-ink-absorbent coating layer 20 is
desired, a representative material suitable for this purpose may
include polyethylene. Other compositions which may be employed to
achieve a non-porous, non-ink-absorbent coating layer 20 include
various organic polymers such as polystyrene, polyethylene
terephthalate, polycarbonate, resins, polytetrafluoroethylene
(e.g., Teflon.RTM.), polyimide, polypropylene, cellulose acetate,
poly(vinyl chloride), and mixtures thereof. In a preferred
embodiment, at least the upper surface 16 of the substrate 12, and
preferably both the upper and lower surfaces 16, 18, are coated
with the selected coating material.
[0052] In another embodiment, the coating layer 20 may include a
wide variety of other ingredients in order to form a more absorbent
layer of material. These various ingredients include, but are not
limited to, one or more pigments, binders, fillers, and other
"supplemental ingredients" such as biocides, hardeners, UV/light
stabilizes, buffers, slip agents, pH control compounds,
preservatives (e.g., antioxidants), lactic acid, and the like. Of
primary concern in connection with such a coating layer 20 is the
use of at least one or more pigment compositions in combination
with at least one or more binders. Exemplary pigments which may be
employed in connection with the coating layer 20 include, without
limitation, boehmite, pseudo-boehmite, silica (in precipitated,
colloidal, gel, sol, and/or fumed form), cationic-modified silica
(e.g., alumina-treated silica), cationic polymeric binder-treated
silica, magnesium oxide, polyethylene beads, polystyrene beads,
magnesium carbonate, calcium carbonate, barium sulfate, clay,
titanium dioxide, gypsum, and mixtures thereof. By way of example
and not limitation, between about 20% and about 90% by weight,
preferably between about 40% and about 70% by weight, pigment may
be employed in the coating composition used to form the coating
layer 20.
[0053] Regarding the use of one or more binder materials in the
coating layer 20, such compositions may include, without
limitation, polyvinyl alcohol and derivatives thereof (e.g.,
carboxylated polyvinyl alcohol, sulfonated polyvinyl alcohol,
acetoacetylated PVOH, and mixtures thereof), starch, SBR latex,
gelatin, alginates, carboxycellulose materials, polyacrylic acid
and derivates thereof, polyvinyl pyrrolidone, casein, polyethylene
glycol, polyurethanes (for example, a modified polyurethane resin
dispersion), polyamide resins (for instance, an
epichlorohydrin-contaiing polyamide), poly(vinyl pyrrolidone-vinyl
acetate) copolymers, poly(vinyl acetate-ethylene) copolymers,
poly(vinyl alcohol-ethylene oxide) copolymers, and mixtures
thereof. By way of example and not limitation, between about 10
parts and about 80 parts by weight, preferably between about 10%
and about 40% by weight, binder materials may be used in the
coating composition used to form the coating layer 20.
[0054] Should any of the other components recited above (namely,
the optional "supplemental ingredients") be employed within this
particular embodiment of the coating layer 20, the amount thereof
may be varied as desired. In this regard, the present invention
shall not be limited to any particular numerical values in
connection with the coating layer 20, with the quantity of binders
and/or pigments in the layer 20 (if used) being reduced
proportionately relative to the amount of any supplemental
ingredients that may be added.
[0055] If a coated substrate 12 is employed, the coating layer 20
shall be construed and defined as part of the substrate 12, with
the representative thickness value "T" associated with the
substrate 12 being suitably adjusted in this regard. Such a
characterization is appropriate since coated paper materials
including those discussed herein are traditionally available in
pre-manufactured form from various paper suppliers and producers.
If a representative photopaper substrate 12 covered on both
surfaces 16, 18 with a gelatin coating layer 20 that may be used is
commercially available in completed form from Hewlett-Packard
Company of Palo Alto, Calif. (USA) under the product designation HP
Premium Photopaper (Glossy).
[0056] If a coating layer 20 is employed on the substrate 12, the
ink-receiving layer 14 may be positioned on the coating layer 20 as
shown in FIG. 1B. If a coating layer 20 is not employed on the
substrate 12 (embodiment not shown), the ink-receiving layer 14
could simply be positioned on the upper surface 14 of the substrate
12. In either instance, the ink-receiving layer 14 is designed and
configured for use as the "top", "uppermost", or "outermost" layer
of material associated with the print media 10. Likewise, the
ink-receiving layer 14 may be configured for direct attachment to
the coating layer 20 or the upper surface 14 of the substrate 12.
However, it shall be understood that the print media 10 may contain
at least one additional layer of material (also known as an
"additional material layer") located above or below the
ink-receiving layer 14.
[0057] Examples of print media 10', 10'' which employ an additional
layer of material are schematically illustrated in FIGS. 2C and 3C,
respectively. This additional material layer (likewise
characterized herein as a "medial layer", or "intermediate layer"
in the embodiment of FIGS. 2C and 3C) is shown at reference numeral
22. In the embodiment of FIG. 2C, the additional material layer 22
is positioned over and above (e.g., operatively attached to) the
ink-receiving layer 14 and is therefore "supported by" the
ink-receiving layer 14. The ink-receiving layer 14 is positioned
over and above the top or upper surface 24 of the additional
material layer 22 and is supported thereby. In the embodiment of
FIG. 3C, the additional material layer 22 is positioned over and
above the upper surface 14 of the substrate 12 (with or without the
coating layer 20) and is therefore "supported by" the substrate 12.
In a preferred embodiment, the additional material layer 22 is
"directly affixed" to the upper surface 14/coating layer 20 or
ink-receiving layer 14 (i.e., without any intervening materials or
layers therebetween). Likewise, in the embodiment of FIG. 3C, the
ink-receiving layer 14 is positioned over and above (e.g.,
"supported by") the top or upper surface 24 of the additional
material layer 22 with "direct affixation" of such components being
currently preferred. A thickness value "T.sub.3" associated with
the additional material layer 22 may be from about 1 .mu.m to about
50 .mu.m, preferably between about 10 .mu.m and about 40 .mu.m.
[0058] The additional material layer 22 may be made from a number
of different ingredients including, but not limited to, pigment
compositions, binders, fillers, defoamer compositions, lubricants,
UV/light stabilizers, biocides, agents, preservatives (e.g.,
antioxidants), general stabilizers, ink fixatives, and hardeners,
used alone or in combination without restriction. All of the
ingredients recited above in connection with the ink-receiving
layer 14 may also be employed within the additional material layer
22, alone or in various combinations, without limitation regarding
the number, type, and quantity thereof. Thus, all of the data
listed herein involving the ink-receiving layer 14 and the various
compositions which can be used in the ink-receiving layer 14 is
equally applicable to the additional material layer 22 and
incorporated in the current discussion by reference. For example,
the additional material layer 22 may contain at least one pigment
composition (without any binders), at least one binder (without any
pigment compositions), or a mixture of at least one pigment and at
least one binder. Furthermore, one or more of the other
additional/supplemental materials recited above in connection with
the ink-receiving layer 14 can also be employed, with the
additional material layer 22 not being limited in connection with
any types, amounts, or quantities of ingredients, as previously
stated. In one embodiment, the print media 10'' may include an
additional polymer-enriched material layer positioned between the
substrate 12 (whether coated or uncoated) and the ink-receiving
layer 14 that functions as a reservoir and provides capacity to
absorb the ink materials.
[0059] The present invention further comprises a coating
formulation (also characterized herein as a "coating composition")
that is used to produce the ink-receiving layer 14 of the present
invention. It is currently preferred that the coating formulation
be in fluidic (e.g., "fluid-containing") form and contain at least
one liquid carrier medium, if desired. Exemplary carrier media
include, without limitation, water, organic solvents (e.g.,
n-methyl pyrrolidone, 2-propanol, or butanol), or mixtures thereof,
with water as the sole carrier medium being currently preferred.
The coating formulation may contain, in one embodiment, at least
one anionic fluorosurfactant and any of the supplemental/additional
ingredients recited above in connection with the ink-receiving
layer 14. In this regard, the foregoing discussion of these
supplemental ingredients is incorporated in the current discussion
by reference.
[0060] Regarding the liquid carrier medium, it is currently
preferred that from about 50 parts to about 100 parts (more
preferably between about 80 parts and about 100 parts) be utilized,
with the balance involving organic solvents such as n-methyl
pyrrolidone, 2-propanol, butanol, or mixtures thereof without
limitation. The coating formulation may typically have a solids
content of at least about 20 parts or more, with a currently
preferred solids content range being between about 20 parts and
about 45 parts (more preferably between about 25 parts and about 40
parts).
[0061] The present invention further comprises a method for
producing a print media 10 of the present invention. Initially, a
substrate (with or without a coating layer 20) is provided (FIG.
1A). Subsequently, at least one ink-receiving layer 14 comprising
at least one anionic fluorosurfactant and, optionally, one or more
additional components (as previously discussed) is formed over and
above the substrate 12 (and/or coating layer 20 associated
therewith, if present) as shown in FIG. 1B. A number of different
techniques may be employed to apply, form, or otherwise deliver the
ink-receiving layer 14 in position over and above the substrate
12/coating layer 20. Formation of the ink-receiving layer 14 is
typically accomplished by coating the substrate 12/coating layer 20
with the coating formulation discussed above. A number of different
delivery/coating methods may be implemented for this purpose
including, but not limited to, the use of a conventional slot-die
processing system, Meyer bar apparatus, curtain coating system, rod
coating device, brush delivery applicator, spraying unit, or other
comparable techniques/devices including those that employ
circulating and non-circulating coating technologies. An exemplary
coating weight range associated with the ink-receiving layer 14
(irrespective of the coating method that is employed) is between
about 5 g/m.sup.2 and about 30 g/m.sup.2 (more preferably between
about 10 g/m.sup.2 and about 20 g/m.sup.2) with reference to the
completed (e.g., dried) ink-receiving layer 14. However, the
claimed invention and its various embodiments shall not be
restricted to any particular layer application/formation methods
(and coating weights) with a number of different alternatives being
employable.
[0062] Once the above-listed coating composition is applied to the
substrate 12 (or coating layer 20), it shall be characterized
hereinafter as the ink-receiving layer 14. After this step, the
substrate 12 having the ink-receiving layer 14 thereon is
preferably dried. This may be accomplished by heating the substrate
12/ink-receiving layer 14 combination at a preferred and
non-limiting temperature of between about 80.degree. C. and about
120.degree. C. (preferably between about 90.degree. C. and about
110.degree. C.) within a conventional oven-type heating apparatus
of a variety normally used for fabricating sheet-type print media.
The substrate 12/ink-receiving layer 14 combination will typically
move through the heating apparatus at a representative "web speed"
of between about 150 and about 800 feet/minute (preferably between
about 250 and about 600 feet/minute). However, it shall also be
understood that other drying methods may be implemented without
limitation provided that the compositions associated with the
ink-receiving layer 14 are effectively dried at this stage. The
overall thickness of the print media 10 illustrated schematically
in FIG. 1B, may readily be determined by simply adding up all of
the aforementioned thickness values "T", "T.sub.1", and "T.sub.2"
associated with the substrate 12, coating layer 20 (if used), and
ink-receiving layer 14, respectively. The total thickness of the
print media 10 can, of course, be appropriately varied depending on
the number of additional layers that may be employed within the
print media 10.
[0063] It will be understood and appreciated by those of ordinary
skill in the art that if one or more additional material layers 22
are utilized, whether above or below the ink-receiving layer 14,
such additional material layers 22 may be formed as previously
discussed with regard to the ink-receiving layer 14 and that the
method hereinabove set forth may be varied accordingly. An
embodiment of the method, wherein an additional material layer 22
is formed over and above the ink-receiving layer 14 subsequent to
the ink-receiving layer 14 being formed over and above the
substrate 12 (including a coating layer 20 in this exemplary
embodiment), is shown in FIGS. 2A-2C. An embodiment of the method,
wherein an additional material layer 22 is formed over the upper
surface 14 of the substrate 12 (including a coating layer 20 in
this exemplary embodiment) prior to formation of the ink-receiving
layer 14 over and above the upper surface 24 of the additional
material layer 14, is shown in FIGS. 3A-3C.
[0064] It should be noted that each of the embodiments described
herein and shown in each of the drawing figures are basically
"one-sided" with the ink-receiving layer 14 and any layer(s)
thereunder or thereover (with the exception of the coating layer
20) being located on only one side of the substrate 12.
Nonetheless, other print media encompassed within this invention
may involve placement of the foregoing layers on either or both
sides of the substrate 12 (coated or uncoated), if desired, without
limitation. Taking this information into account, the use of "on"
the substrate, "over and above" the substrate, "operatively
attached to" the substrate, "supported by" the substrate, "affixed
to" the substrate, and the like when describing the layering
arrangements discussed herein shall encompass both "one-sided" and
"dual-sided" media sheets. This language will specifically be
understood to involve situations in which the subject layers are
placed on either or both sides of the substrate 12. However, if a
substrate 12 is employed which includes a coating layer 20 thereon,
the ink-receiving layer 14 and any layer(s) thereunder or thereover
may be positioned on the side(s) of the substrate 12 that is coated
with the coating layer 20, irrespective of the materials employed
within the coating layer 20 and/or the ink-receiving layer 14.
[0065] The following examples describe the formation of a print
media 10 employing an ink-receiving layer 14 in accordance with a
particular embodiment of the present invention in comparison to
print media employing prior art ink-receiving layers. The examples
are merely illustrative and are not meant to limit the scope of the
present invention in any way.
EXAMPLES
Example 1
Ink-Receiving Layer Comprising Nonionic Fluorosurfactant
[0066] A photobase paper manufactured and commercially available
from the Felix Schoeller Company of Germany was obtained. A first
layer comprising 8.4 g gelatin (available from, for example, DGF
Stoess AG of Eberbach, Germany) and 7.02 g 88% hydrolyzed PVOH
obtained from Clariant Corporation of Charlotte, N.C. (USA) under
the product designation PVOH 2688, was applied to the upper surface
of the coated photobase substrate. This polymer enriched layer
functions as a reservoir and provides capacity to absorb the ink
vehicle.
[0067] An ink-receiving layer was subsequently applied over and
above the first layer, the ink-receiving layer comprising 0.5 g
gelatin, 0.5 g proprietary styrene-acrylate copolyme, 1.25 g PVOH
2688, 0.25 g cellulose, and 0.0075 g Lodyne.RTM. S107B, a
commercial nonionic fluorosurfactant obtained from Ciba Specialty
Chemicals, Inc. of Tarrytown, N.Y. (USA).
Example 2
Ink-Receiving Layer Comprising Nonionic Fluorosurfactant
[0068] A coated photobase substrate having a polymer-enriched layer
and first layer as described hereinabove was prepared as previously
set forth in Example 1. Subsequently, an ink-receiving layer was
applied over and above the first layer, the ink-receiving layer
comprising 0.5 g gelatin, 0.5 g proprietary styrene-acrylate
copolymer, 1.25 g PVOH2688, 0.25 g cellulose, and 0.0075 g
Zonyl.RTM. FSN, a commercial nonionic fluorosurfactant obtained
from Dupont of Wilmington, Del. (USA).
Example 3
Ink-Receiving Layer Comprising Anionic Fluorosurfactant
[0069] A coated photobase substrate having a polymer enriched layer
and first layer as described hereinabove was prepared as previously
set forth in Example 1. Subsequently, an ink-receiving layer was
applied over and above the first layer, the ink-receiving layer
comprising 0.5 g gelatin, 0.5 g proprietary styrene-acrylate
copolyme, 1.25 g PVOH 2688, 0.25 g cellulose, and 0.0075 g
Zonyl.RTM. FSA, a commercial anionic fluorosurfactant obtained from
Dupont of Wilmington, Del. (USA).
Example 4
Comparative Performance Analysis
[0070] A substrate prepared according to each of Examples 1-3 above
was subsequently dried in a conventional oven-type heating
apparatus of a variety normally used for fabricating sheet-type
print media at a temperature of approximately 100.degree. C. Then,
the dried substrates were run through a PHOTOSMART.RTM. P100
printer unit (available from the Hewlett-Packard Company of Palo
Alto, Calif. (USA)) and images comprising cyan, yellow, magenta,
black, light cyan, and light magenta were printed thereon.
[0071] As compared to the substrates comprising ink-receiving
layers having a nonionic fluorosurfactant, the substrate prepared
in accordance with Example 3 exhibited smaller dot sizes.
Particularly, the light cyan dot size was approximately 4
micrometers smaller than the light cyan dot sizes of the other
substrates. In addition, the rubber marking was improved with
Example 3 listed in Table 1. TABLE-US-00001 TABLE 1 Rubber Marking
Comparisons Examples Rubber Marking #1 bad #2 bad #3 good
[0072] Light fastness performance was also improved with Example 3
and is listed in Table 2. TABLE-US-00002 TABLE 2 Light fastness
Comparison Examples Light fastness (years to fail) #1 8.6 #2 11.2
#3 15.3
[0073] Although the foregoing description contains many specifics,
these should not be construed as limiting the scope of the present
invention, but merely as providing illustrations of some exemplary
embodiments. Similarly, other embodiments of the invention may be
devised which do not depart from the spirit or scope of the present
invention. Features from different embodiments may be employed in
combination. The scope of the invention is, therefore, limited only
by the appended claims and their legal equivalents, rather than by
the foregoing description. All additions, deletions and
modifications to the invention, as disclosed herein, which fall
within the meaning and scope of the claims, are to be embraced
thereby.
* * * * *